The International Cessna^® 170 Association

A recent thread discussed wiring. Can anyone give me an approximate number of feet of each size wire needed for a complete rewire. Thanks

The size and lengths of wire required to completely rewire your plane to stock configuration are in the parts manual. The only draw back is you have to do the math, (add each length of wire together for each particular use). In otherwords add all of the 22 guage, all the 20 guage, etc., to get your totals. I know it's alot of adding, but that will get you in the ball park for what you need. I don't know of a source that has already done this, and that is the only way I know to get close to the figure you are looking for. Jon

I'm working on this exact question as we speak. I should have an answer in a day or two.

Bruce

N171TD wrote:A recent thread discussed wiring. Can anyone give me an approximate number of feet of each size wire needed for a complete rewire. Thanks

Really.....the only place you can go, depending on the load and other factors, is AC 43.13-1B chapter 11 and figure it out for your self......Brad

Finally sat down and did the math on how much wire is in our airplanes. These numbers were taken from the the Association's 170 Electrical System Service Manual figure 72 for serial numbers 25373 and on. I listed two numbers for 14 and 18 gauge wire. The smaller number is that required for the landing lights (14 gauge) and nav lights (18 gauge). You would subtract these numbers from the total if your airplane, like mine, has had these wires previously replaced or you only wanted to replace the wires withing the cabin and immediate areas. The numbers have been rounded up to the nearest foot. I do not guarantee my math

Gauge length
4 : 3'
10: 9'
14 : 46'/32'
18 : 141'/60'
18 shielded : 12'

Haven't priced it yet...

Thanks for your reply. Hope your rewire goes well. Bet these numbers will help others when ordering wire for their planes.
Good luck with Sharkey

That "4"-gage wire is for the battery and starter circuit, and although Cessna used that, it's not the best choice due to the amps that flow thru that wire, expecially at start. I recommend using "2" gage wire for that purpose. (Also for the ground service plug, if you install one.)

Trying to place an order to do this same thing.
Can you suggest a quantity, type and size of terminals to purchase?

Seafeye wrote:Trying to place an order to do this same thing.
Can you suggest a quantity, type and size of terminals to purchase?

I would have to know the status of your current set-up (i.e., whether or not you had a ground-service AN plug, which battery setup, etc etc.)

Measure your present setup and examine the present terminals and add a foot for good measure.

(PS. my own is set up with 00 copper and copper terminals, but that is a bit of overkill because I had it already on-hand.)

Battery is still in the front right side of engine compartment. No service port, although this sounds like a good idea.
The airplane is strictly VFR and I have no plans to change that. I enjoy the current view.
I was thinking of going the circuit breaker route. I like the Klixon ones. http://www.chiefaircraft.com/kli-7277-2.html
Everything else is pretty standard, I think, just one radio and transponder. I got a quote of $1000 to Rewire the airplane/radios. Personally I'd like to do it myself but I don't have a hangar nor the time right now. The squirrel nest under has me a bit worried, and of course 65 year old wiring might be past the best before date.

Seafeye wrote:Trying to place an order to do this same thing.
Can you suggest a quantity, type and size of terminals to purchase?

Do you mean just for the battery and starter cables? Like George said, measure what you've got and order new. Either 2 or 4 gauge is sufficient for the short runs you need for the battery and starter. The resistance of 2 gauge is 0.156 milliohms per foot, and 4 gauge is 0.249. That means if you pass a current of 1000 amps through them you'll get a voltage drop of 156mV in the 2 gauge and 249mV in the 4. Starters draw a lot less than that, so the drop in the copper itself is insignificant.

The terminals, on the other hand, are important. You need to make a good crimp to get good conductivity, and for that you need a real crimper. My mechanic lets me use his. The terminals are spec-ed by wire gauge and stud size. You'll have 1/4" and 5/16" studs on the solenoids. Maybe 3/8". Measure them. Order here.

When you make the new cables, attach one terminal, then bend the wire into the shape you want, leaving good loop size to minimize stress, and then cut, strip and crimp on the other end. If you attach both terminals to a straight cable you'll never be able to bend it into shape, nor twist it to get the terminals into the right orientation. And don't forget to slip the two pieces of shrink tubing onto the wire before you attach the other terminal!

And don't forget.... these electrical repairs are NOT "preventive maintenance" and must be performed under the direct supervision of an A&P to be legal.
( I mention this not because I'm trying to be a legal-stickler...but because your questions reveal you are unfamiliar with this level of work and I would hate for you to find out you've created an expensive problem for yourself. The Electrical System Service Manual the Assoc'n is recently offering for sale might be found useful if they still have any left.)

Yes, very aware of the limitations. I wouldn't want to put any I/A in that position anyway. But would like to put in the order for supplies so they are on hand.

And don't forget to slip the two pieces of shrink tubing onto the wire before you attach the other terminal!

I can't tell you how many times I've made that mistake...

An avionics shop owner I talked to echoed what George suggests in this thread-- Add a jumper between the firewall and the engine.

Some time back I found that the 14 gauge wire called out in the IPC for the landing lights is inadequate. See if your I.A. agrees with what I wrote here.

Mechanics for years to come will call you "Blessed" if you go to the trouble of labeling your wires. If you can't borrow a wire stamper use the smallest font on your laser printer to make your wire labels and then attach these with clear heat shrink.

In addition to AC43.13-1B mentioned above I found a lot of good information in Bob Nuckoll's book although it seems geared to the experimental builders.

In addition to using aircraft wire and terminals make sure you use the correct tools. The Craftsman crimper shown below should be reserved for the Datsun. If members need to borrow my crimper and/or wire stripper send me a private message.